Photovoltaic cells or solar cells are photovoltaic components for direct generation of electrical current from sunlight. Due to the growing demand for clean sources of energy, the manufacture of solar cells has expanded dramatically in recent years and continues to expand. Various types of solar cells and solar cell substructures exist and continue to be developed. For example, solar cells include a substrate, a back contact layer on the substrate, an absorber layer on the back contact layer, a buffer layer on the absorber layer, and a front contact layer above the buffer layer. In some types of solar cells, the front contact layer can include a layer of transparent conductive oxide (TCO) material forming a window for light to pass through to the other layers below.
A plurality of solar cells are formed on one substrate, and are connected in series by respective interconnect structures in each solar cell to form a solar cell module. The absorber layer absorbs the sunlight that is converted into electrical current using the back contact layer. As such, semi-conductive materials are used in the manufacturing or fabrication of at least some known solar cells by being used as the material to form the absorber layer. More specifically, chalcopyrite based semi-conductive materials, such as copper indium gallium sulfur-selenide (CIGSS) (also known as thin film solar cell materials), are used to complete the formation of the absorber layer.
Some techniques that are used for the formation of CIGSS or thin film solar cell materials include a selenization process of metal precursors and a sulfurization process that is conducted after the selenization (the entire process is referred to as sulfurization after selenization (SAS)).